1. Field of the invention
This invention relates to a method of forming a separator for a cylindrical battery (for example, organic electrolyte batteries, alkaline zinc batteries, and the like) which includes cylindrical or columnar positive and negative electrodes disposed concentrically through a separator.
2. Description of the prior art
In batteries with such a structure described above, separators, which are previously molded so as to form a cylindrical and closed-ended structure, have been generally employed.
In order to save a step for previously forming the above cylindrical separator, a method of making a battery has been recently proposed which includes winding a separator several times over around an electrode located at a center of the battery, and welding a residual portion of the lower end of the separator or welding after twisting it, thereby closing the separator (see Japanese published examined patent application No. 41690/1979).
On the contact condition between the electrode and the separator in this method, the separator is only wound around the electrode, and therefore it is not sufficiently contacted to the electrode to cause a gap therebetween. Consequently, there are provided such problems that since the possessory volume of the separator in the battery is increased, the volume efficiency within the battery is lowered, and that as the distance between electrodes becomes large, the internal resistance of the battery is increased to lower the battery performances.